Ok, my 92 LS 400 (85000 miles) let me down this morning, and I am trying to figure out the problem. Any help would be greatly appreciated. The LS400 has been a great car in the 5 months I have owned it, but not this morning! When I accelerated onto the main road from my neighborhood, the car would not accelerate past 15/20 mph. It felt like the car died, as the engine was lugging badly. The rpm level wouldn't go over 2000 either, which makes me think this is not a transmission issue. In drive, the car just won't surpass 2000 rpm or 15/20 mph. Strange, I think? Nothing is leaking, but there was a smell coming from the car once I pulled back into the driveway.

Does anyone have any ideas of what this may be? I heard that these cars may have a built in Engine defense where if the Engine has issues, the car won't let you accelerate past a certain speed, to protect the engine of sorts? Any help would be greatly appreciated. Thanks!

I had a similiar problem, it was the fuel pump resister relay. it is located under the rear of the air filter housing. It is about 3" x 1.5" silver with cooling ribs and a 2 wire plug going to it. You can find them reasonable on EBAY, do not buy a used one. You can also bypass it to make sure this is the problem. Just remove it and connect the wires on the plug together.
Bob